1. Field of the Invention:
The present invention pertains to pressure-responsive devices and more particularly to a pressure transducer suitable for accurately converting pressures into a useful electrical signal.
2. Description of the Prior Art:
In order to achieve accurate pressure measurement, the prior art has generally employed vibrating devices, wherein the elastic vibrations of the structural material is converted into an electrical output. Both vibrating diaphragms and vibrating cylinders have been employed in the prior art. These require a driving mechanism to move the vibrating element. As a result, such prior art vibrating devices have been complex and are relatively fragile.
Other pressure transducers hertofore known in the art have employed deflecting diaphragms in a variety of configurations. Due to mechanical hysteresis, creep, and nonlinearity, such diaphragm transducers have lacked the desired accuracy and precision. While some deflecting diaphragm transducers known in the prior art have been rugged, it has not been possible to combine the desired accuracy and repeatability with the ruggedness required for airborne or oceanographic instruments.
In addition, in the case of vibrating instruments, pressure is determined by measuring the resonant frequency of the mechanical elements subjected to pressure. Such sensors are density-sensitive, and are limited to gaseous media. Changing from one gas to another, such as from air to bottled nitrogen, for example, requires different calibration of the frequency-pressure characteristic.